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BezierCurve

BezierCurve​

Cubic Bezier Curve class.

Consists of a start point, an end point, 2 control points, and the bounding box for the curve.

Link to an interactive cubic bezier curve with formulas: https://www.desmos.com/calculator/rptlhv5rx8.

Constructor​

public BezierCurve​

new BezierCurve(p1, p2, c1, c2)

Initializes bezier curve with the given start point, end point, and intermediate points. If no point(s) are given, then it will be initialized with a blank Vector. Bounding Box holds meaningless values by default.

Parameters

  •  p1: Vector – Initializes start point with given coordinates.

  •  p2: Vector – Initializes end point with given coordinates.

  •  c1: Vector – Initializes first control point with given coordinates.

  •  c2: Vector – Initializes second control point with given coordinates.

Properties​

No publicly accessible properties on BezierCurve

private p1: Vector​

The x, y coordinates of the start point.

private p2: Vector​

The x, y coordinates of the end point.

private c1: Vector​

The x, y coordinates of the first control point.

private c2: Vector​

The x, y coordinates of the second control point.

private boundingBox: Transform​

The Bounding Box that encases the entire curve.

private dirty: false | true​

Whether the curve's data has been updated.

Methods​

private getT​

getT(a, b, c, mod, end) => number

Calculates t by using the quadratic formula with the given a, b, and c.

Parameters

  •  a: number – The a value in the quadratic formula.

  •  b: number – The b value in the quadratic formula.

  •  c: number – The c value in the quadratic formula.

  •  mod: 1 | -1 – The +/- in the quadratic formula.

  •  end: number – Returns end if result is undefined.

Returns

  •   number – The value of t, where t represents how far along the bezier curve the given point is.

private updateBoundingBox​

updateBoundingBox() => void

Calculates the position and size of the bounding box, based on p1, p2, c1, and c2.

public setP1​

setP1(v) => void

Changes start point (P1), for Bezier curve.

Parameters

  •  v: Vector – The x, y coordinates to set the point to.

public setP2​

setP2(v) => void

Changes end point (P2) for Bezier curve.

Parameters

  •  v: Vector – The x, y coordinates to set the point to.

public setC1​

setC1(v) => void

Changes first control point (C1) for Bezier curve.

Parameters

  •  v: Vector – The x, y coordinates to set the point to.

public setC2​

setC2(v) => void

Changes second control point (C2) for Bezier curve.

Parameters

  •  v: Vector – The x, y coordinates to set the point to.

public getP1​

getP1() => Vector

Returns start point of curve (p1).

Returns

  •   Vector – The x, y coordinates of the start point.

public getP2​

getP2() => Vector

Returns end point of curve (p2).

Returns

  •   Vector – The x, y coordinates of the end point.

public getC1​

getC1() => Vector

Returns first control point (C1) for Bezier curve.

Returns

  •   Vector – The x, y coordinates of the first control point.

public getC2​

getC2() => Vector

Returns second control point (C2) for Bezier curve.

Returns

  •   Vector – The x, y coordinates of the second control point.

public getX​

getX(t) => number

Calculates x coordinate of t.

Parameters

  •  t: number – How far along the bezier curve the given point is.

Returns

  •   number – The x coordinate of t.

public getY​

getY(t) => number

Calculates y coordinate of t.

Parameters

  •  t: number – How far along the bezier curve the given point is.

Returns

  •   number – The y coordinate of t.

public getPos​

getPos(t) => Vector

Calculates x and y coordinates of t.

Parameters

  •  t: number – How far along the bezier curve the given point is.

Returns

  •   Vector – The x and y coordinates of t.

public getDX​

getDX(t) => number

Calculates the 1st derivative of x coord of t.

Parameters

  •  t: number – How far along the bezier curve the given point is.

Returns

  •   number – The 1st derivative of x coord of t.

public getDY​

getDY(t) => number

Calculates the 1st derivative of y coord of t.

Parameters

  •  t: number – How far along the bezier curve the given point is.

Returns

  •   number – The 1st derivative of y coord of t.

public getDerivative​

getDerivative(t) => Vector

Calculates the 1st derivatives of x and y coordinates of t.

Parameters

  •  t: number – How far along the bezier curve the given point is.

Returns

  •   Vector – The 1st derivatives of x and y coordinates of t.

public getDDX​

getDDX(t) => number

Calculates the 2nd derivative of x coordinate of t.

Parameters

  •  t: number – How far along the bezier curve the given point is.

Returns

  •   number – The 2nd derivative of x coordinate of t.

public getDDY​

getDDY(t) => number

Calculates the 2nd derivative of y coordinate of t.

Parameters

  •  t: number – How far along the bezier curve the given point is.

Returns

  •   number – The 2nd derivative of y coordinate of t.

public get2ndDerivative​

get2ndDerivative(t) => Vector

Calculates the 2nd derivatives of x and y coordinates of t.

Parameters

  •  t: number – How far along the bezier curve the given point is.

Returns

  •   Vector – The 2nd derivative of x and y coordinates of t.

public getBoundingBox​

getBoundingBox() => Transform

Bounding box accessor updates the bounding box and returns it.

Returns

  •   Transform – A Transform that contains the bounding box of the curve.

Static Methods​

No static methods for BezierCurve